The perimeter of the Kincade Fire at 1:09 a.m. PDT October 28, 2019 seen in relation to the Tubbs and Pocket Fires on October 24, 2017. Click to enlarge.

When the wind is blowing at 50 to 90 mph not much can stop a wildfire, but the footprints of two fires that burned in October of 2017, the Tubbs and Pocket Fires, may have had some limited effect on the spread of the Kincade Fire that started last week.

When a wildfire burns into a two-year-old fire scar, usually there is much less vegetation than what had been carrying the fire — fewer tons per acre and lighter fuels. For example if moving from chaparral to grass, the intensity, the amount of heat produced, and number and size of fire brands generated would be much less. That does not mean the fire would go out on it’s own, but unless the weather is extreme, like it has been in northern California off and on for the last week, there would be less resistance to control. In other words, easier to put out.

In some cases with very steep slopes or heavy fuels such as very dense brush or timber, retardant dropped from an aircraft might have little effectiveness in dry windy conditions. But in the lighter vegetation that follows a fire, aircraft can be very efficient in slowing the spread long enough to allow firefighters on the ground to move in and actually suppress it.

During the extreme weather in northern California the last few days the Kincade Fire spread partially into the Pocket Fire on the north and the Tubbs Fire on the south. On the map above take note of the unburned red polygon, or island, inside the perimeter of the Pocket Fire.

During extreme winds and single-digit humidity a fire can keep spreading until it runs completely out of fuel, but it would be interesting to hear from folks that were on the Kincade Fire to find out if there was any significant change in fire intensity when it moved into the two fire scars.

In a brief submitted to a federal court, the California Attorney General wrote that Pacific Gas & Electric could be prosecuted for murder, manslaughter or lesser criminal charges if investigators determine that “reckless operation” of its power equipment caused any of the wildfires in which people were killed during the last 15 months.

A dozen of the fires that started in Northern California around October 8, 2017 have been blamed on PG&E’s electrical equipment, according to CAL FIRE Investigators, who also are looking into power line equipment failures that may have caused the Camp Fire on November 8, 2018. Over 40 people died in the Northern California fires, and 86 perished in the Camp Fire. More than 14,000 homes were destroyed in the Camp Fire.

Shortly after both events the stock price of PG&E dropped precipitously, sinking 66 percent over the 13-month period. It took several days in 2017 for word to spread that the company appeared to be liable for the Northern California fires, but the sell-off began the day after the Camp Fire started in 2018. Investors are worried that the utility could be on the hook for billions of dollars in civil damages in addition to criminal penalties.

Below is an excerpt from the Sacramento Bee:

The legal brief submitted by [Attorney General Xavier] Becerra’s office said prosecutors would have to gauge PG&E’s “mental state” before determining which charges, if any, to bring. The charges would range from murder to a misdemeanor negligence charge, according to the brief. Becerra’s brief is purely advisory; if any criminal charges are filed, they would likely be lodged by county district attorneys, not the state.So far, though, district attorneys have shown little appetite for prosecuting PG&E, according to Sacramento Bee reporting. No charges have been filed yet in the wine country fires. And at least one DA has opted for a financial settlement in lieu of criminal prosecution

A screenshot from the ABC10 video below, shot by an officer’s body cam.

In the video below produced by ABC10, law enforcement officers and firefighters tell their stories about encouraging residents to evacuate during the first hours of the Tubbs Fire that burned into Santa Rosa, California October 9, 2017. One firefighter explains how he kept working after learning that his house was one of the hundreds that were destroyed. Body cam footage gives us an up close viewpoint of what the first responders were going through. The North Bay fires destroyed about 8,900 structures (including homes and outbuildings).

Today I was reading an article about how the communities in Northern California are dealing with the risk from wildfire. One item that got my attention was where a “forestry and wildfire specialist” was quoted describing the Fountaingrove area of Santa Rosa which was devastated by the Tubbs Fire in October of last year.

…a housing development in a rural area that had been built following the highest fire safety standards. Vegetation had been cleared as required, and the homes were built of fire-resistant materials.

The article correctly stated that the development had been “reduced to ashes by the Tubbs Fire”.

“How could that have happened?”, I thought. Fire resistant building standards and cleared vegetation? Firefighters know that if those two characteristics can be checked off, a structure has a much better chance of survival. So how did the community get wiped out?

The Fountaingrove community is 4 miles north of the intersection of Highways 101 and 12 in Santa Rosa. The Tubbs Fire, the deadliest of the fires in 2017, burned into the north section of Santa Rosa, including the Fountaingrove area. It killed 22 people, destroyed 5,643 structures, and burned 36,807 acres.

I would not call Fountaingrove a “rural area”. The thousands of homes there are very tightly packed, as you can see in the satellite photo below taken about five months before the Tubbs Fire.

Satellite photo of an area in Fountaingrove May 17, 2017, before the Tubbs Fire. Google Earth.

The next three photos are all of the same area, showing structures on Fir Ridge Road before and after the Tubbs Fire of October, 2017.

Fir Ridge Road area of Fountaingrove before the Tubbs Fire. Google Maps.

Satellite photo of the Fir Ridge Road area in Fountaingrove, June 16, 2017. Google Earth.

Satellite photo of the Fir Ridge Road area in Fountaingrove, October 17, 2017. Google Earth.

The photo below was taken before the fire, a few blocks south of the ones above. This home and all others around it burned.

A home on South Ridge Road in Fountaingrove before the Tubbs Fire. Google Maps.

The Fountaingrove area burned in the 1964 Hanley fire. During the 53-year period until the next fire, the 2017 Tubbs Fire, the houses grew back along with a great deal of vegetation. Most of the homes have shrubs in the yards and multiple large trees, often between the houses that are very close together. Some of the structures are partially obscured from aerial photos by limbs hanging over the roofs.

It is difficult to tell if the homes in these photos were constructed of fire resistant materials. But it is clear that other Firewise principles were not being followed.

Firewise vegetation clearance recommendations. NFPA.

In a fireprone environment there should be no flammable material within 5 feet of a structure, and in the Home Ignition Zones 5 to 100 feet away, trees need to be 6 to 18 feet apart depending on the distance from the building. If on a slope, these distances have to be increased substantially.

An excellent video that elaborates on these principles has been produced by the NFPA. It points out that the areas in between the trees do not have to be nuked. But to be fire resistant they need to consist of green grass or fire resistant small plants, and should be raked or mowed close to the ground.

If a structure meets these Firewise guidelines, it stands a much better chance of surviving a wildfire. However, if the weather conditions are extreme, such as 60 mph winds and single digit humidity which can lead to spot fires igniting a mile ahead of the main fire, it can be difficult to save a structure.

Most homes are ignited not by the main flaming front of a fire, but from burning embers that land out ahead and start new fires. Likely receptors for these embers are leaves in a gutter, mulch, wooden decks, lawn furniture, attic vents, and accumulations of dead grass, pine needles, leaves, and other flammable material.

When a community is initially planned, the engineers may have done some things right, such as the design of the streets, and water systems. But if everything else is left up to the knowledge and discretion of developer and homeowner, very important principles might be ignored.

Fountaingrove did not meet all of the Firewise guidelines, but the streets were wide, making it easier for large fire trucks to access the structures. The very close spacing of the homes means that if one burns, the radiant heat alone can ignite its neighbor.

Other things to consider in mitigating the wildfire threat include multiple evacuation routes — if one becomes compromised by the fire, another could remain open. Large open spaces without flammable vegetation can serve as safety zones for residents who can’t escape. Backup electrical power sources that can keep pumps running so that community water tanks remain full can ensure firefighters have water at hydrants.

With the warming climate leading to extreme fires and fire seasons that are nearly year round, it is inevitable that deadly fires will strike many wildland-urban interface communities. Under the conditions we have seen in recent years, casually ignoring the threat will lead to more fatalities and property damage. It is not IF a fire will hit a fire prone area, but WHEN. The best solution is to learn to live with and adapt to fire, not ignore it.

Many factors can lead to an area being vulnerable to wildfire, including fire suppression leading to a buildup of vegetation, density of homes like at Fountaingrove, failure of homeowners to use Firewise principles, lack of community standards, insurance companies not understanding the issue, the federal government reducing expenditures for vegetation management and prescribed burning, lawsuits that halt vegetation management projects, and cutting the numbers of firefighters, air tankers, and Type 1 helicopters. When politicians take hold of just one of these issues while ignoring the rest, it can make it impossible to have a rational conversation about adapting to fire.

Discussions need to be thorough and nuanced, not politicized and influenced by industry that profits from using just a single, ill-conceived concept. And zeroing in on one vague term like “raking” and “poor forest management” simply confuse the general public when the complete picture is not illuminated.

Investigators looking into the cause and origin of the large wildfires that plagued Northern California last fall have determined that a Pacific Gas and Electric power line started the Cascade Fire in Yuba County. The blaze started on the evening of October 8 and burned a total of 9,989 acres, destroyed 264 structures, and resulted in four civilian fatalities and one firefighter injury.

“A high wind event in conjunction with the power line sag on two conductors caused the lines to come into contact, which created an electrical arc”, the California Department of Forestry and Fire Protection (CAL FIRE) said in a news release. “The electrical arc deposited hot burning or molten material onto the ground in a receptive fuel bed causing the fire. The common term for this situation is called ‘line slap’ and the power line in question was owned by the Pacific Gas and Electric Company.”

The investigative report for the Cascade Fire was forwarded to the Yuba County District Attorney, which is the usual practice. The D.A. decided that no violations of the Public Utilities Code in regard to vegetation management were found and made no other recommendations regarding criminal action, including the offense of involuntary manslaughter.

In total, the October 2017 Fire Siege involved more than 170 fires and burned at least 245,000 acres in Northern California. Approximately 11,000 firefighters from 17 states and Australia helped battle the blazes.

Earlier CAL FIRE said an additional 16 fires during the siege were attributed to PG&E equipment, alleging violations of state law in 11 of those incidents. CAL FIRE still hasn’t released its report on the Tubbs blaze, the deadliest of last year’s fires, which killed 22 people, destroyed 5,643 structures, and burned 36,807 acres.

In a news release PG&E addressed the CAL FIRE report about the Cascade Fire:

We look forward to the opportunity to carefully review the CAL FIRE report to understand the agency’s perspectives.

The safety of our customers, their families and the communities we serve is our most important job. Without question, the loss of life, homes and businesses in these extraordinary wildfires is heartbreaking and we remain focused on helping communities recover and rebuild.

In the meantime, we are continuing to focus on implementing additional precautionary measures intended to further reduce wildfire threats, such as working to remove and reduce dangerous vegetation, improving weather forecasting, upgrading emergency response warnings, making lines and poles stronger in high fire threat areas and taking other actions to make our system, and our customers and communities, even safer in the face of a growing wildfire threat.